1. Field of the Invention
The present invention relates to an insect killing system used for killing insect pests such as orange files (strumeta dorsalis) and melon flies (aulacophora femoralis) which stick to raw fruit such as papayas, mangos, green peppers or the like.
2. Description of the Prior Art
It has been conventionally known that maggots or eggs of insect pests such as orange flies or melon flies sticking to papayas, mangos or the like could be killed out by means of a steaming treatment (under the operating conditions of; temperatures within a killing system of 43.degree.-49.degree. C.; fruit core (product) temperatures of 41.degree.-41.7.degree. C.; a humidity of 90%-100%; and, a treatment time of 3 hours.). Such treatment, however, has not been put to practical use so far, because it requres a high accuracy for the temperature and humidity conditions. In other words, in case of small-scale or experimental steaming treatment, the above-mentioned temperature and humidity conditions can be maintained constant for the treatment hours, but it has been found difficult to steam treat raw fruit on a larage sscale. For example, in case where the raw fruit is containted in a harvest box, it is difficult to satisfy the above-mentioned preselected temperature and humidity conditions for the raw fruit which is located in the center of the harvest box, and thus it is not possible to kill out the maggots and eggs of the orange flies attaching to all of the raw fruit.